Isolated alkali salts of indoxyl and process of making same.



mwnacorr ALBRECHT scHMID or ocHsT-omTHnuvrsm, GERMANY, ASSIGNOB o .ranswnm .vonm. MEISTER LporUs & entinma, or HocHsT- QN THE I1:AIN, ens-mans, a mess.

PORATION or GERMANY.

ISOLATED ALKALI SALTS or. mnoxrr. AND endorse or MAiIN65AME.

N o Drawing.

- To all whom it may concern Be it known that I, ALBRECHT ScHMmT, Ph. 13., chemist, a citizen of the Empire.

of Germany, residing at, Hochst-on-the- 'Ma1n, Germany, have invented cert-amnew and useful Improvements in Isolated Alkali Salts of Indoxyl and Processes of Making Same, of which-the following isa specification. V f I As. .known', by melting phenylglycin', its

.' derivatives or homologues (or Similar mmpounds yielding iiidoxyl derivativw, that is to say indoxyl oriits substitution products,-by. alkaline'melt), for instance with 15 alkali hydrate. or with a mixture of alkali hydrate and sodium amid, or with'sodium" (see British specifications NOS." 16875 of- 1901 and 13059 of 1901),- indoxyl melts are obtained containing a large quantity of free "caustic alkali. Hitherto, thesemelts have drate and the alkali combined with the indoxyl; By operating in this manner all the alkali was lost. =liloreo"er-, the indoxyl was partially decomposed since it is but little stable, when in a .free state.

4 other is of much technical importance. It.

"hydrate diflicult. a Now, according tothe present invention,

renders possible the transformation of the indoxyl into indigo in slightlyalkaline or neutral or slightlyacidsolutions, or in solutions so much'diluted. that, if this dilution were used in the direct treatment of the indoxyl melts,- t-he recouery of the alkali hydrate would no longer be profitable. This separation of the indoxyl is also of importa'nc for the purpose of'transforming the indoxylintoindigoin presence of bodies which impart to the precipitated indigo a certain physical constitutionysuch, tor instance, as inorganic diluents which are entirely or partlally soluble 1n-alkal1' hydratcs,

. or salts of fatty acids, or glue, any of which,

it added; to the solution of the indoxyl melt would render the recovery of the alkali iiidoxyl can be separated in ayery advan- Application filed Septenier 2g, ism. serial However the separation of the indoxyl in some form or dition,: with 100 parts of ice.

Specification of Letters lzfient.

tageousmannec in the i of crystalline :alkah. salts, hitherto unknown as such, by adding to the initvxyl melt a limited quanea-ans May 23,19ii 2r tity of water, preferably while cooling or can by .use of ice. lAfterthe mixture has stirred for some time the new-alkali salt of: the indoxyl separates almost completely in the form f0f brilliant larhinae- .Thc highly concentrated caustic alkali lye I thus forn cd causes the p'recipitationoftlie alkali i-ndoxyl. By filtering the mass throughen asbestos or a sand filter, or subjecting 'itto centrifugal action, there is obtained, on the one hand, an alkali indoxyl cont-aining only a comparatively small quantity of adhering alkali hydrate, which can be removed by su1t-abl'e"mean s, for instanceby pressure or subsequent washing with ah'ighly concentrate d-salt solution, and on the other hand a highly concentrated alkali lye, containing only a small quantity of indoxyl, which can be directly used again or from which the 'small quantity of indoxyl contained in it may be separated in the form of indigo by blowing air into it after having diluted it with water. According to the quantity of water-used it .is possible, either to increase the yield of crystallized, indoxyl salt by u'S-jj ring very little water' and thereby 'separating less completely the alkali hydrate which adheres to the indoxyl salt orpartially' .crys-' tall-izes'with it, or to separate in a more perfect-manner. the alkali hydrate fromthe crystallized indoxyl salt, so that-the latter is obtained in a purer-and therefore:still more suitable condition for further. transformations, foregoing in this case a large yield of crystallized indoxyl salt. In any case the filtrate is used f0r the production,

of indigo. p

The following example illustrates the invention:' 100 parts by weight of indoxyl melt-- prepared'according to Example 1 of -the British specification No. 13059 of 1901, are stirred. preferablyin a pulverized con- A hot solution is thereby first formed, from .which, on stirring and cooling, there soon separates a. crystalline magma, consisting of, brilliant laminae. This magma is filtered or-pressed. It still contains a sinall'quantity of caustic alkali hydrate, which, if required, can be removed'even more completely by washing with water or by diluting with alittle water,

BEST AVAILABLE COPY ,01 with caustic alkali lye. .111 Li! 1 mi iudnx vl in n. wfliF. 'iwim ii-mu iin" n kriim. mlvnntageuus to useh'om 'uzc z s 41f 'ylxeiiylgkrcm, n Ji's clicking litile more water, or to (i k-avail; indicated and, after the 01- dilute with a little more ivaiel. :x'sthere'is used iu-tlm mail. musm. we caustic potash, the alkali an a are obtained in the form of indny or indoxyl potassium having 2.2.

oxyl derivatives by alku m: molt, com in (linking such melt, ore?- liugg in ch :1 $1"-;1ll qunh flu; alkali salts. imlo f inim. i in a solid fmrm. being ervs Mine. whereirl "31 stands for an ulkal fl vellmxfin lnmimv. suiuhlo 'in wiii'cer iiui also salts of l l thus l I liOl. in the luitef to a reddish-brown soluyellowish bodies CIZVStamZQdlH, the tiou. capable of l rlll" ncciyfifntml from (he which dissoh'e in almlml to cuneemiatuil 801M601? in miter in the form l'eddlsll-bl'own Solution: 3150inwutei'iwmch of Yulluwisll lamina: in' means of an; cur-35:; can b l'elllecil)itated from the 501mm in of :ilkali I'm-drum. andEopuruting incli 'o luv Water. in the form of j'ellowisn laminae, by 5 gm ti 'bf m I D means of ext-e55 of alkali hydrate, and which I t stimony whereof. I m i se mrzlte indigo by the action of iii!' '2 in .qfpgmgfe of two .k c

Having thus described the nature of my 3. w, m

said invention and the best means I know of i AL l E carrying the same into practical effect, Witnesacsv claim: i JEAN (mum), l. The processof separating alkali salt-s (hm GRUNLI. 

